Digital information recording apparatus, reproducing apparatus and transmitting apparatus

ABSTRACT

A digital information recording apparatus includes a recording circuit for recording information of a retention period included in the digital information and indicating a period for permitting the digital information to be held in the recording medium, starting with a time at which the digital information is recorded on the recording medium; and information of a playback permission period included in the digital information and indicating a period for permitting the digital information to be played back starting with a time at which the information is reproduced initially following recording of the digital information on the recording medium, permitting temporary recording or copying for the information permitted for “copy never” or “copy one generation.”

CROSS REFERENCE TO RELATED APPLICATION

This application is a Cont. of U.S. application Ser. No. 16/703,071,filed Dec. 4, 2019, now U.S. Pat. No. 10,854,237, issued Dec. 1, 2020which is a Cont. of U.S. application Ser. No. 15/690,640, filed Aug. 30,2017, now U.S. Pat. No. 10,529,372, issued Jan. 7, 2020, which is aCont. of U.S. application Ser. No. 14/713,515, filed May 15, 2015, nowU.S. Pat. No. 9,773,522, issued Sep. 26, 2017, which is a Cont. of U.S.application Ser. No. 13/649,882, filed Oct. 11, 2012, now U.S. Pat. No.9,083,942, issued Jul. 14, 2015, which is a Cont. of U.S. applicationSer. No. 11/834,340, filed Aug. 6, 2007, now U.S. Pat. No. 8,311,389,issued Nov. 13, 2012, which is a Cont. of U.S. application Ser. No.09/982,291, filed Oct. 19, 2001, now abandoned, which claims priorityfrom Japanese patent applications JP 2001-002053, filed Jan. 10, 2001,JP 2000-384891, filed on Dec. 13, 2000 and JP 2000-393271, filed Dec.21, 2000, the contents of which are incorporated by references.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an apparatus for recording orreproducing digital information such as video and audio data, moreparticularly, to digital information recording and reproducing apparatuscapable of setting a limit to playback or copying of the information tobe recorded or reproduced by the authority of copyright holders and thelike. Further, the present invention relates to a transmitting apparatussuitable for transmitting digital information to the recording andreproducing apparatus as above.

Description of the Related Art

Digital television broadcasting has been started and digital recordingand reproducing apparatus for recording and reproducing digitalinformation have been brought to market. In addition, even in the fieldof package medium such as movie software, package software to be usedwith this type of apparatus will be developed and practiced in the nearfuture.

The digital recording scheme has an advantage that the quality is notdeteriorated or very less degraded in the recording and reproducingprocess. But in the event that many high-quality copies are prepared andcirculated at a site unknown to a copyright holder, there arises aproblem that profits cannot be returned to the copyrighters. This is apending problem for which countermeasures have been discussed in variousfields since a case of digital audio tape deck at issue.

For example, JP-A-11-146378 discloses a method of preventing preparationof high-quality copies by degrading the quality in advance of digitallyrecording information.

U.S. Pat. No. 5,896,454 discloses a method of adding copy controlinformation of 2 bits to data information. In the method, any one ofcopy inhibition, copy approval and copy approval for only one generationis selected of volition of copyright holders or information planners tocontrol the operation of a recording apparatus. The recording apparatusdoes not perform recording operation if copy inhibition is selected butperforms recording operation if copy approval is selected. With copyapproval for only one generation selected, the recording apparatusrewrites this control information into information for inhibiting anymore copies and then operates to record.

In other words, the copy control information useful for the informationdata planner to control copying operation by users has been proposed.For example, codes of “copy never” (copy inhibition), “copy onegeneration” (for permitting only one copy), “no more copies” (data oncecopied through “copy one generation” is not permitted for more copies)and “copy free” (approval of copying) are set in a header part of dataor a watermark (WM), very difficult to detect, is embedded in an image.The above expedient is expected to solve the problem without inflictinga one-sided loss on the copyright holders or users.

But, even in case the stringent inhibition, for example, “copy never” isimposed, there is obviously a spontaneous need for temporarily recordinginformation on, for example, a hard disc of a receiving apparatus andplaying back the information and therefore, with a view of mitigating aloss on the side of users, a means for this purpose is necessary. Atthat time, it must also be considered to mitigate a loss on the side ofcopyright holders.

More particularly, when a visitor comes accidentally while the copycontrol information being set to “copy never” in broadcasting, a user inquestion disadvantageously looses a chance of playing back a broadcastprogram. Under the circumstances, JP-A-2000-149417 discloses a method ofeliminating such a problem by using a means “temporary recording” evenwhen the copy control information designates “copy never”. According tothe method, information is once recorded physically on a recordingmedium and a limit of 90 minutes for instance is set to the period forreproduction and playback and the information is erased after a playbackor at the termination of the period. In other words, the recording isnot for long-term conservation and multipurpose utilization but simplypermits the broadcasting to be equivalently played back 90 minuteslater. Since the information on the recording medium does not remain fora long time, the aforementioned inconvenience of users can be eliminatedwithout inflicting an unprofitableness to the copyright holders. Thetemporary recording is, because of its nature, carried out frequently byusing a hard disc recorder built in the receiving apparatus.

SUMMARY OF THE INVENTION

Various kinds of expedience disclosed in the above documents give asolution to the problems. But the problem involved in copyright cannotbe solved satisfactorily by the conventional methods that inflictone-sided profit or loss to copyright holders, broadcasting or softwaredeveloping firms or general users.

Further, the “copy one generation” conveniently gives the users a chanceof backing up the information recorded temporarily on a hard disc forinstance. As a rule, once the temporarily recorded information iscopied, the copy control information changes to “no more copies” toprevent any more copying. But, when copying of the temporarily recordedinformation is permitted, though only once, the copy permission remainsfor a long time, giving anxiety to the copyright holders. On the otherhand, when “no more copies” is once set, desired exchange of the mediumstoring the contents becomes impossible and disadvantageously the usersare forced to suffer from inconvenience.

In the light of the above problems, an object of the present inventionis to provide more specifically a unit for preventing circulation ofunauthorized copies and permitting the user to perform conditionalplayback and the like.

Another object of the invention is to provide a unit for eliminating theaforementioned anxiety of the copyright holders and inconvenience of theusers through a method of meeting the compatibility between profits ofthe user and the copyright holder.

Still another object of the invention is to provide a unit for limitinga condition for permitting playback of recorded information for instanceso as to enable the copyright holder to further control the range ofinformation utilization.

According to the invention, the effective period, available inside arecording medium, of information permitted for temporary recording isprescribed. The apparatus has a unit for disabling reproduction andplayback after expiration of a prescribed time following recordinginitiation. Through this, the information temporarily recorded on themedium can be prevented from being used later for unauthorized purposes.The effective period inside the recording medium referred to herein willbe called “retention period”. Further, the effective period startingwith playback initiation is also prescribed. The apparatus has a unitfor disabling repetitive reproduction and playback after expiration of aprescribed time following the initial start of playback. Through this,playback by many and unspecified users can be prevented. The effectiveperiod referred to herein will be called “playback permission period”.

Frequently, the retention period is set to be equal to or longer thanthe playback permission period but this is not limitative. Many types ofreproducing apparatus cause their operation to temporarily pause or stopduring reproduction. Accordingly, even when reproduction is startedduring the playback permission period, the retention period sometimeshappens to stop or end before the playback comes to an end. In thatcase, concurrently with the stop of the retention period, reproductionis disabled to proceed any more. Alternatively, for convenience ofusers, even with the retention period stopped, a part of informationsucceeding the stopping location is once allowed for continuous playbackup to the end. In that case, conditionally, further pause and stop areinhibited.

In some case, a part once subjected to playback is inhibited forrepetitive playback. This can be implemented by disabling backward feedof the medium or making, in some way, a part once subjected to playbacknon-reproducible during backward feed.

When the copyright holder originally sets a limit to copying such as“copy one generation” for instance, copying permitted for the user islimited to some extent. To prevent the temporarily recorded informationfrom staying in the medium for a long time while being conditioned to“copy one generation”, the present invention prescribes the effectiveperiod for the information, conditioned to “copy one generation” to stayin the recording medium following, recording of the information. Theapparatus has a unit for handling the information as being subject to“no more copies” after expiration of the prescribed period followingrecording so as to prevent copying, thereby eliminating anxiety of thecopyright holder about the long-term stay of the information subject to“copy one generation”. The effective period referred to herein will becalled “copy permission period”. In the medium in which the copypermission period has expired or information is copied within the copypermission period, the copy control information changes to “no morecopies” to disable copying.

In that case, by permitting “move” operation for moving the informationto another medium on the presupposition that the original information isto be erased, inconvenience of the user can be obviated. As necessary,the period for permitting the move mode after the control informationhas changed to “no more copies” or the period for permitting repetitivemove after the preceding move may be prescribed. The effective periodreferred to herein will be called “move permission period”.

When the operation is caused to temporarily pause or stop duringreproduction even if copying is started during the copy permissionperiod, the move permission period will sometimes be stopped before itcomes to an end. In that case, concurrently with the stoppage of thecopy permission period, any more copying is inhibited. Alternatively,for convenience of the user, even with the copy permission periodstopped, a part succeeding the stop location can once be allowed forcontinuous copying up to the end. In that case, conditionally, furtherpause and stop are inhibited.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features and advantages of the presentinvention will become more readily apparent from the following detaileddescription when taken in conjunction with the accompanying drawingswherein:

FIG. 1 is a block diagram showing an embodiment of the configuration ofthe whole of a digital information transmitting, receiving, recordingand reproducing system to which digital information recording apparatus,reproducing apparatus and transmitting apparatus according to theinvention are applied;

FIG. 2 is a block diagram showing an embodiment of the digitalinformation transmitting apparatus according to the invention;

FIG. 3 is a block diagram of a digital information receiving side inFIG. 1;

FIG. 4 is a block diagram showing an embodiment of a recording circuitin the digital information recording apparatus according to theinvention;

FIG. 5 is a block diagram showing an embodiment of a recording andreproducing unit in the digital information recording apparatus andreproducing apparatus according to the invention;

FIG. 6 is a block diagram showing an embodiment of a reproducing circuitin the digital information reproducing apparatus according to theinvention;

FIG. 7 is a block diagram showing another embodiment of the reproducingcircuit in the digital information reproducing apparatus according tothe invention;

FIG. 8 is a diagram showing an embodiment of the structure of firstcontrol information according to the invention;

FIG. 9 is a diagram showing an embodiment of the structure of copycontrol information according to the invention;

FIG. 10 is a diagram showing an embodiment of the structure of secondcontrol information according to the invention;

FIG. 11 is a diagram showing an embodiment of recording data onrecording medium according to the invention;

FIG. 12 is a block diagram showing still another embodiment of thereproducing circuit in the digital information reproducing apparatusaccording to the invention;

FIG. 13 is a block diagram showing another embodiment of the recordingcircuit in the digital information recording apparatus according to theinvention;

FIG. 14 is a block diagram showing another embodiment of the digitalinformation reproducing apparatus according to the invention; and

FIG. 15 is a block diagram showing an embodiment of an erasing circuitin the digital information reproducing apparatus according to theinvention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is a block diagram showing an overall configuration of atransmitting, receiving, recording and reproducing system including aninformation distributor. The present invention involves a recordingapparatus, a reproducing apparatus and a transmitting apparatus, havinga reproducing circuit 1, a recording circuit 2, an informationdistributor 3 such as a broadcasting station, a repeater 4, a tuner forRF (radio frequency) 5, a recording/reproducing unit 6 and a display 7.

The information distributor 3 such as a broadcasting station transmits asignal electromagnetic wave modulated with information through themedium of the repeater 4 such as, for example, a broadcasting satellite.Otherwise, transmission based on a cable may be employed. The RF tuner 5on the receiving side receives and demodulates the transmittedinformation and thereafter, the recording circuit 2 converts it into asignal suitable for recording on a recording medium and therecording/reproducing unit 6 records the converted signal. Therecording/reproducing unit 6 also reproduces the information from therecording medium. A reproduction signal is applied to the display 7through the reproducing circuit 1 to ensure playback of the informationrepresenting original video and audio data. Though not illustrated, thereceived information can also be played back directly. In caseinformation recorded in advance on a removable recording medium isserviced, only the operation succeeding the reproducing operation by therecording/reproducing unit 6 is carried out.

FIG. 2 is a block diagram showing an embodiment of the construction ofthe information distributor 3 (transmitting apparatus) such as abroadcasting station. The transmitting apparatus comprises a programgenerator 31, an encode circuit 32 for performing compression based on,for example, MPEG scheme, a scrambler circuit 33, a modulator circuit34, a transmitting antenna 35, a service information applying circuit 36and an input terminal 37.

The amount of data in information such as video/audio informationgenerated by the program generator 31 constituted of a camera orrecording/reproducing device is compressed by the encode circuit 32 sothat the information may be transmitted with a less bandwidth. Asnecessary, the information is encrypted by means of the scramblercircuit 33 to enable a specified audience to take part in playback. Theencrypted information is modulated to a signal suitable for transmissionby means of the modulator circuit 34 and then is emitted from thetransmitting antenna 35 in the form of an electric wave directed to therepeater such as, for example, a broadcasting satellite. In this phase,the service information applying circuit 36 adds information such ascopy control information and retention information and playback/copypermission period information. In addition to the above information, thepresent time information may be applied which can be utilized as a startpoint of the retention period and copy permission period. For example,request information is inputted to the input terminal 37 through atelephone line for instance. This is utilized for the case where theinformation to be transmitted is determined in response to a requestfrom audiences as exemplified by video-on-demand.

FIG. 3 is a block diagram showing an embodiment of the RF tuner 5 shownin FIG. 1. The RF tuner 5 includes an RF/IF converter circuit 51, ademodulator circuit 52, a descrambler circuit 53 for decoding ordecrypting the cipher applied to the signal and an output terminal 54.

An electric field from the repeater, for example, a broadcastingsatellite is inputted to the RF/IF converter circuit 51. The RF-bandelectric wave is converted in frequency to a frequency of IF(intermediate frequency) band or is converted into a signal of aconstant band independent of a receiving channel. The demodulatorcircuit 52 releases the modulation operation applied for the purpose oftransmission. The cipher in the demodulated signal is then decrypted bythe descrambler circuit 53 and then delivered to the output terminal 54.

FIG. 4 is a block diagram showing an embodiment of the recording circuit2. The recording circuit 2 has an input terminal 201 for a signal to berecorded, a memory circuit 202 such as a semiconductor memory, arecording signal processing circuit 203, an output terminal 204 for asignal to be recorded on a recording medium, an information detectioncircuit 205, a recording control circuit 206, a clock 107 and an inputterminal 208 for records of a control signal during reproduction.

The signal inputted through the input terminal 201 is applied withvarious control codes. As an example, a signal applied with the copyinformation “copy never” and designated with the aforementionedretention period and playback permission period will be described. Inthe case of broadcasting, the data as above is applied to theinformation by means of, for example, the service information applyingcircuit 36 of FIG. 2. The inputted data is once stored block by block inthe memory circuit 202. Then, the data is fed to the informationdetection circuit 205 which in turn detects the control informationconcerning copying. Subsequently, the recording control circuit 206decides on the basis of the data as above whether the signal ispermitted for recording and sends a decision result to the recordingsignal processing circuit 203. The recording signal processing circuit203 has already been applied with the data from the memory circuit 202and on the basis of the control signal from the recording controlcircuit 206, it interrupts the signal when recording is inhibited butapplies a modulation suitable for the medium used when recording ispermitted, thus delivering a modulated signal to the output terminal204. The output signal is recorded on a medium such as a tape or disc.For example, even when the control information is “copy never”, theoutput signal is recorded temporarily on the medium if the effectiveretention period and playback permission period are designated.Obviously, instead of being detected by the information detectioncircuit 205, the control signal may be applied externally, separatelyfrom video/audio data.

When recording is permissible, the information including the copycontrol information and the retention period and playback permissionperiod is generated by the recording control circuit 206 and is added tothe recording signal by means of the recording signal processing circuit203. As necessary, the present time during recording delivered out ofthe clock 107 is also recorded concurrently. If the present time isincluded in the received information, this data may be used or the clock107 may be set by the received information. Through this, the presenttime during recording can be prevented from being altered.

With the aforementioned control information being “copy any generation”,if the effective copy permission period is designated or the movepermission period is designated as necessary, information is recordedtemporarily on the medium while keeping “copy one generation” unchanged.In case the control information is “no more copies”, copying isinhibited as a rule and therefore, the output of, for example, therecording signal processing circuit 203 is interrupted. In the case ofan apparatus in which the aforementioned move mode is permitted,however, recording of information onto the medium is permitted even for“no more copies” on the premise that a counterpart of the information onthe side of the apparatus transmitting that information will be erased.In that case, it is sometimes necessary to transmit, to the apparatus onthe recording side, information as to whether the erase operation of thetransmitting apparatus is adapted to the move mode. Instead of detectingthe control information inclusive of such information as just mentionedabove by means of the information detection circuit 205, thatinformation may be applied externally separately from the video andaudio data.

If the aforementioned move permission period is additionally designated,even the apparatus adapted to the move mode is not permitted to do movewhen the above move permission period runs out or expires.

Even with the detected control information being “copy one generation”,in the absence of information such as copy permission period, thecontrol information is changed to “no more copies” by means of therecording signal processing circuit 203 during recording.

FIG. 5 is a block diagram showing an embodiment of therecording/reproducing unit 6 shown in FIG. 1. The recording/reproducingunit 6 includes an input terminal 61, a recording amplifier 62, arecording media drive 63 carrying a recording medium such as a harddisc/digital video disc/video tape, a reproducing amplifier 64, anoutput terminal 65, a mechanism control circuit 66 and an input terminal67.

The output signal of the recording circuit 2 is supplied to the inputterminal 61. This signal is amplified by the recording amplifier 62 soas to be able to drive a laser generation device or a magnetic head andis then recorded on the recording medium as above by means of therecording media drive 63. A signal reproduced from the recording mediumis amplified by the reproducing amplifier 64 up to a level that canafford to be processed in the succeeding stage of signal processing andthereafter delivered to the output terminal 65. The mechanism controlcircuit 66 is for a motor used to drive the recording media drive 63 andis responsive to a control signal inputted to the input terminal 67 tocontrol the recording medium. Though not illustrated, the control signalinputted to the input terminal 67 is fed from the recording circuit 2 orreproducing circuit 1.

FIG. 6 is a block diagram showing an embodiment of the recording circuit1 of the information reproducing apparatus according to the invention.The reproducing circuit 1 includes an input terminal 101 for areproduction signal, a reproducing signal processing circuit 102, ablock detection circuit 103, a memory circuit 104 such as asemiconductor memory, an error correction circuit 105, a signal outputcircuit 106, a clock 107, a decoder 108 for decoding moving picturecompression, a watermark detection circuit 109 for decryption of awatermark embedded in an image, an output terminal 110 for sending asignal to the display, an information detection circuit 111 for controlsignals, an output control circuit 112 for deciding, on the basis of acontrol signal, whether delivery of a reproduction signal ispermissible, an output terminal 113 for the signal kept away fromdecoding of the cipher, an output terminal 114 for a decision result,and an output terminal 116 for the control information delivered to theinput terminal 208 of recording circuit 2.

The following description will be given by way of a case in which dataconcerning the aforementioned retention period and playback permissionperiod are included in the reproduction signal supplied to the inputterminal 101. The signal is fed to the reproducing signal processingcircuit 102. In this circuit, the modulation applied on the recordingside for the purpose of performing recording/reproduction on/from themedium is demodulated, the waveform equalization is carried out and datais settled by a clock. Subsequently, in the block detection circuit 103,synchronization and ID signals are detected, on the basis of thesesignals, reproduction data is once stored at a predetermined location inthe memory circuit 104. The error correction circuit 105 detects fromthe stored data a code error generated in the course of recording andreproduction through arithmetic operation to provide a corrected value.Data subject to error correction is sent to the decoder 108 through thesignal output circuit 106.

An output of the signal output circuit 106 is also supplied to theoutput terminal 113 so as to be used for further copying by a differentrecording device connected to this terminal 113. But in the case of asignal applied with stringent copy limit as described previously, thesignal delivered from this output terminal is subject to “copy never”and therefore, copying often fails to fulfill itself. An output ofoutput control circuit 112 to be described later may be supplied to thesignal output circuit 106 to prevent the signal from being delivered tothe output terminal 113.

On the other hand, from the data applied with the previous errorcorrection, the information detection circuit 111 for control signaldetects data indicative of the retention period and playback permissionperiod. One data detection operation per one frame of an image sufficesto provide sufficient information as will be described later and thedata may be set to the header of a recording track in the case of, forexample, a tape medium. Alternatively, the data detection operation asabove may be once performed at intervals of a predetermined amount ofdata. If that data is recorded frequently, thinning-out detectionoperation may be carried out during reproduction. Then, the outputcontrol circuit 112 decides, on the basis of the detected retentionperiod and playback permission period as well as playback start time,time for recording and the present time from the clock 107, whether thedelivery of reproduction output is permissible, thereby controlling theoutput to the decoder 108. The information detection circuit 111 mayalso detect the control signal for “copy never” and “no more copies” inorder for the output of the output control circuit 112 to control thesignal output circuit 106, thus ensuring that when copying is inhibited,the delivery of the reproduction signal to the output terminal 113 canbe prevented.

The output of the output control circuit 112 is also applied to theoutput terminal 114. This output signal is used when the signal detectedby the information detection circuit 111 includes information forconditionally permitting a device connected externally to carry outrecording/reproduction, in order to transmit the information to theoutside. When it is determined that the retention period has alreadyexpired, information indicative of this expiration may be supplied fromthe output terminal 114 to the aforementioned input terminal 67 of FIG.5 to stop the recording media drive 63.

The moving image data compression applied in advance of the transmissionby the decoder 108 is decoded from the output of the signal outputcircuit 106 and a resulting signal is fed to the output terminal 110 topermit playback with the display connected to the output terminal 110.As the output from the output terminal 110, an intact decoded digitalsignal may be delivered or an analog signal converted from the digitalsignal may be delivered.

When a copyright holder, copy control information and the like areembedded as a watermark in an image, the watermark detection circuit 109operates to detect the watermark. In place of the signal detected by theinformation detection circuit 111, the information detected from thewatermark may be used to perform a similar control operation.

The clock 107 is of course required of accuracy to some extent. If theclock can easily be altered with malicious intent of the user, then itwill not fulfil itself. Further, it is desirable that the clock becontrollable in response to time information from, for example, thebroadcasting station. The clock may be designed to make the apparatusinoperative when the time is altered intentionally.

Next, in connection with the case in which the reproduction signalapplied to the input terminal 101 includes data concerning theaforementioned copy permission period, only operation differing fromthat described as above will be described. In this case, the informationdetection circuit 111 for control signal detects data of the copycontrol information, for example, “copy one generation” and the copypermission period. The output control circuit 112 decides, on the basisof the detected control information and copy permission period as wellas recording time and the present time from the clock 107, whethercopying is permissible and sends a decision result to the signal outputcircuit 106. If the copy information “copy one generation” is availablewithin the copy permission period, the signal output circuit 106 passesthe reproduction signal. On the medium of the external device forpreparation of copies, the control signal is changed to “no morecopies”. If the copy information “copy one generation” is outside thecopy permission period, the control information can be rewritten to “nomore copies” to disable the external device to copy. As necessary, theinformation in the medium may be rewritten to “no more copies” by meansof the recording circuit. Obviously, rewrite on the reproducing side bythe signal output circuit 106 is not limitative and it may be done withanother reproducing circuit block.

FIG. 7 is a block diagram showing another embodiment of the reproducingcircuit according to the invention. Constituent components identical tothose in the FIG. 6 embodiment are designated by identical referencenumerals. The present embodiment differs from the FIG. 6 embodiment inthat the decoder 108, watermark detection circuit 109 and outputterminal 110 are removed. These components are often built in thedisplay 7 of FIG. 1 and in that case, the reproducing circuit isseparated as a unitary circuit, leading to the construction shown inFIG. 7. On the basis of the information, such as retention period,playback permission period, copy permission period and copy controlinformation, detected by the information detection circuit 111, theoutput control circuit 112 sends a control signal to the signal outputcircuit 106 in order to control permission/inhibition of the delivery ofthe signal to the outside and rewrite of the control information. Thesignal at the output terminal 113 can be supplied to the display as wellas another external recording device as in the case of the FIG. 6embodiment.

FIG. 8 is a diagram showing an embodiment of a first control signaltransmitted from the information distributor 3 and recorded on therecording medium during recording in the foregoing embodiments. In thecase of a tape medium for instance, recording of one first controlsignal on one recording track suffices but obviously, the first controlsignal is recorded in a predetermined relationship with video and audiodata to assure easy separation of the first control signal duringreproduction. Program number 300 indicates what number is allotted to aprogram in question on the medium. Sector information 301 indicatesnumbers allotted to sectors set up by dividing the program in apredetermined unit. The division can be made in a fixed unit, forexample, in a unit of 2k bytes or in a constant unit of information, forexample, in a unit of division during encoding. The numbers may be setup within the program or may be serial numbers set up throughout therecording medium. Information such as recording time 305 to be describedlater is added in a unit of sector. Time information 302 indicates howlong the recording part of interest proceeds after start of the program.Type information 303 indicates attribute information of the program asto whether the program is sold, rental, self-made or distributed frombroadcasting. Copy control information 304 indicates the aforementionedcontrol information such as “copy never”, “copy one generation” or thelike.

FIG. 9 shows a structure of the copy control information 304. Versionnumber 311 indicates which version the information belongs to. As willbe described later, the copy control information 304 must be so flexibleas to add some items other than those shown in FIG. 9 or to erase someitems from FIG. 9, as necessary. Accordingly, with a view of determininghow what information is arranged in sequence in various ways, theversion is managed. For example, when 8 bits are allotted to the versioninformation 311, the copy control information 304 can be used in 256ways.

Output control 312 controls the permission/inhibition of delivery of theoutput from the digital output terminal 113 or the analog outputterminal 110. For control of the output delivery, it is first decided,from the form of the output and encryption conditions, whether safetycan be assured and then the permission/inhibition of the output deliveryis controlled. Further, the output delivery permission/inhibition may becontrolled depending on resolution for instance. For example, in thecase of a video signal of high resolution such as high vision video,control is such that the video signal as it is may be inhibited frombeing delivered but a video signal set up by degrading the resolutionmay be permitted for delivery.

Copy control information 313 (CGNS; Copy Generation Management System)controls copying to a digital recording device. For example, when thisinformation is of 2 bits, “11” may designate “copy never”, “10” maydesignate “copy one generation”, “01” may designate “no more copies” tothe effect that one copy obtained through “copy one generation” is nomore permitted for copying, and “00” may designate “copy free”.Different CGMS's may be provided for the digital signal output andanalog signal output, respectively.

Copy control information 314 (APS; Analog Protection System) controlscopying to an analog recording device. A psuedo-sink pulse may be addedto an analog video signal for the purpose of controllingpermission/inhibition of copying.

Move mode 315 is information concerning permission/inhibition of “move”.The term “move” means that information is copied onto a different mediumand thereafter, a counterpart of that information recorded on theoriginal medium is erased. This ensures that only one copied informationpiece can always be allowed to exist, making it possible to keep thecondition that many repetitive copying operations result insubstantially one copying operation. When information subject to “copyone generation” is copied in the normal copy mode, any more copying isprevented by changing the copy control information to “no more copies”but when the move mode proceeds, the copy control information is againreturned to “copy one generation” so that the information of interestcan be sent to the copying destination to enable the sent information tobe copied and after the copying, the original information is erased. Themove mode 315 may prescribe the move permission count in addition to themove permission. In that case, the move permission count information maybe decremented each time that a move operation is carried out. Forexample, when the move mode 315 is of 4 bits, the permission countranging from 0 to 15 can be defined. In this case, the definition may besuch that even when all of the 4 bits are “1111”, the count is not 15but is infinite.

Playback count 316 is for prescribing the playback permission count andis ruled as necessary. The playback count is used when, for example, inaddition to a limit set to the effective period by the aforementionedretention period, the playback count is desired to be limited. Like themove permission count, the playback permission count is decremented eachtime that one playback operation is carried out. When all of the bitsare “1” initially, the limitation to the count can be handled as beingnullified.

Playback longevity period 317 is used when the playback operation islimited temporally. For example, when the playback longevity period isof 16 bits to ensure management in a unit of minute, temporal limitationup to about 45 days can be available. For all of the bits being “1”,this period can also be handled as designating unlimitedness. If theCGMS 313 is “copy never”, the rules in the aforementioned playbackpermission period for instance are predominant in connection with thetemporal limitation to the playback operation. Accordingly, the rules inthe playback longevity period 317 are used as information available inan instance excepting the above. In an alternative, the playbacklongevity period 317 may be incorporated into the playback permissionperiod so as to be handled as unified information.

Pause period 318 prescribes a period for permitting a pause operation(temporary stop). The pause period can be handled similarly to theplayback longevity period 317. More particularly, it happens thatplayback operation is required to be stopped temporarily on urgentbusiness due to a visitor. In such a case, the pause period is used totemporally limit the temporary stop.

Delayed start time 319 is used, to limit time for starting working.While the aforementioned retention period sets a limit to working,starting with the recording time, the delayed start time 319 permitsworking, starting with absolute time such as 12.00 p.m., Jan. 1, 2001for instance. This is suitable to permit simultaneous disclosures at atime. After the delayed start period has elapsed, information ispermitted for playback and delivery for instance. As the delayed starttime, the absolute time may be described or a difference time (relativetime) from a time (for example, 12.00 p.m., Jan. 1, 1970) agreed bypersons in the same line of business may be described. If all of thebits are “0”, the recording time may be the start time.

Not all contents of the copy control information 304 are necessary andsome of the contents can be omitted. Further, move permissible period307B to be described later may arranged, for example, between the movemode 315 and the playback count 316, instead of being positioned asshown in FIG. 8.

The recording time 305 in FIG. 8 records, for example, the time of theclock 107 of FIG. 4 or the time supplied from the service informationapplying circuit 36 of FIG. 2. The recording time 305 can be recorded ina unit of sector for instance.

In the present embodiment, information covering retention period 306A,copy permission period 306B, playback permission period 307A and movepermission period 307B is further used. All of the information can beused but only two of 306A and 307A, only two of 306B and 307B or onlyone of, for example, 306B may sometimes be used.

For the information “copy never”, the copyright holder or the softwareproducer rules the retention period 306A and the playback permissionperiod 307A as described previously. For example, the retention periodis set to 9 hours and the playback permission period is set to 2 hours.When there is no need of setting a limit to the period, a code of “nolimit” may be applied. In addition to the above, limitation to theplayback count may be prescribed.

For the information “copy one generation”, the copy permission period306B and move permission period 307B are ruled used similarly and thelatter is applied only when needed. Also, limitation to the movepermission count may be prescribed.

User identification information 308 is recorded when a code inherent toa user is used with the aim of permitting information recorded on themedium to be reproduced by only the same apparatus as that used duringrecording or only the user. Encryption information 309 is used to decodea cipher during playback when information is encrypted and recorded onthe recording medium. This will be described again later with referenceto FIGS. 12 and 13. The information per se has a large amount of dataand therefore, code numbers may be recorded and informationcorresponding to a code number stored in advance may be drawn out bymeans of the reproducing apparatus so as to be used. The information asabove is recorded as necessary at a relatively short temporal pitch, forexample, every image frame or at the rate of predetermined amount ofdata. With the control signal having the structure as above, the presentinvention can be practiced but the structure shown in FIG. 8 is forexplanation only and various kinds of structure, recording position onthe medium and frequency can also be applicable.

FIG. 10 is a block diagram showing a structure of a second controlsignal recorded during reproduction in the present embodiment. Thesecond control information includes playback start time 321, playbackstart sector number 322 and playback stop sector number 323. Theplayback start time 321 records a time counted by, for example, theclock 107 of FIG. 12 to be described later. When a playback is stopped,a sector number at that position is recorded in the playback stop sectornumber 323. Since playback times at sectors on the way can be calculatedfrom the playback start time 321, playback times at all sectors subjectto reproduction can be known. Of course, the playback time can berecorded in a unit of sector.

In the case of the tape medium for instance, when the operation mode isreturned to the stop mode during playback, individual pieces of controlinformation shown in FIG. 10 can be recorded anywhere near the stopposition. The information can also be recorded using, for example, therecording circuit of FIG. 4.

Referring to FIG. 11, the recording position of the control signal onthe medium will be described. FIG. 11 diagrammatically shows recordingpositions of the control signal and information data such as video andaudio data on the recording medium. Recording positions shown at (a) inFIG. 11 are suitable for the tape medium. In this case, the block of thecontrol signal is preferably provided, for example, every recordingtrack. Accordingly, in each track, a block of the control signal isarranged in the header part, for instance, to precede the informationsuch as video and audio data. Recording positions shown at (b) in FIG.11 are suitable for a digital video disc. In this case, the controlsignal and video and audio data are preferably provided every sectorhaving a certain amount of information. Accordingly, they are arrangedat the header part every sector. Recording positions shown at (c) inFIG. 11 are suitable for a hard disc. In this case, the information suchas video and audio data and the control signal are recorded at positionsspaced apart from each other on the disc to permit the whole of thecontrol signal to be read within a short period of time during start. Inan alternative, the first control information may be recorded at theheader part and the second control information may be recorded at aposition spaced apart therefrom. Since the second control information isto be recorded or rewritten during reproduction, it is required to berecorded at an independent or isolated position. Alternatively, insteadof being recorded in the recording medium, the second controlinformation may be recorded in, for example, the memory device or memorycircuit 104 mounted externally of the recording medium or in a memorydevice in an independent apparatus.

Referring now to FIGS. 12 and 13, another embodiment directed to thereproducing circuit 1 and the recording circuit 2. FIG. 12 is a blockdiagram showing a reproducing circuit 1 according to the presentembodiment and FIG. 13 is a block diagram showing a recording circuit 2according to the present embodiment. Constituent components identical tothose in FIGS. 6 and 4 are designated by identical reference numeralsand will not be detailed. The present embodiment is effective when it isrequired that only predetermined users be allowed to take part inplayback or when a fee is charged.

In FIG. 12, there are provided a decryption circuit 131 and an inputterminal 132 for an identification code inherent to the apparatus and inFIG. 13, there are provided an encryption circuit 233 and an inputterminal 234 for an identification code inherent to the apparatus or anapparatus permitted for playback.

In the encryption circuit 233 of FIG. 13, encryption is carried out withthe identification code of the apparatus fed from the input terminal234. Without performing descramble in the RF tuner 5, two kinds ofencryption may be carried out in an overlap fashion. In the decryptioncircuit 131 of FIG. 12, decryption is carried out with theidentification code of the apparatus fed from the input terminal 132. Ifthe identification code is not an authorized one, normal decryptionfails to proceed to thereby prevent the playback from being done.

In the apparatus, encryption with the identification code is exemplifiedbut this code may be added to the aforementioned block of the controlsignal and may be detected on the reproducing side to decide whether thedelivery of signal is permissible.

Encryption may be done in a unit of program but when the encryption iscarried out while changing the key to the encryption in a unit of sectorand individual keys are recorded, an encryption process can be performedin the unit of sector.

Next, an example of operation of controlling the retention period 306Aand playback permission period 307A during reproduction will bedescribed. Firstly, when the difference between recording time 305 of asector to be reproduced and the present time indicated by the clock 107is within the retention period 306A at the initiation of a playback, theplayback is started. At the same time, the playback start time 321 andplayback start sector number 322 are recorded as the second controlinformation. With the playback stopped, a playback stop sector number323 is recorded. With a pause taken, a playback stop sector number 323is recorded as in the case of the stoppage of the playback and with thepause released, a process similar to that at the initiation of theplayback is carried out. More particularly, the time is again confirmedand if the time is within the retention period 306A, playback resumes.When backward feed is done, a playback time at that location isconfirmed and if the difference between the playback time and thepresent time is within the playback permission period 307A, a playbackis permitted. When fast feed is carried out, it can be known byconfirming the second control information that no playback is carriedout throughout a fast feed range. Therefore, when a playback isinitiated, permission/inhibition of the playback is decided by only theretention period 306A regardless of the playback permission period 307A.Namely, a playback longevity period after one playback operation subjectto the playback permission period 307A is controlled for a playbacklongevity period following recording subject to the retention period 6A.

The pause period can also be controlled depending on the playbackpermission period 307A. In this case, permission/inhibition of theinitial playback start is controlled by the retention period 306A andwhen a playback stop is carried out or a pause is taken after start ofthe playback, the period for stoppage is measured in order thatresumption of playback is permitted when the measured period is withinthe playback permission period 307A but resumption of playback isinhibited when the measured period exceeds the playback permissionperiod 307A. Further, by inhibiting the backward feed, it is possible tosteadily permit only one playback operation. In this case, control canbe undertaken without recording the second control information.

In case information under the control of the retention period 306A orplayback permission period 307A is reproduced and then delivered as adigital signal from the output terminal 113, it is conceivable that theretention period 306A or playback permission period 307A of controlinformation added to the information of interest is decremented orzeroed.

Operation when the copy permission period 306A and move permissionperiod 307B are used is as follows. Firstly, if the difference between arecording time 305 of a sector to be reproduced and the present timeindicated by the clock 107 is within the copy permission period 306B atthe playback initiation, normal playback is started and a reproductionsignal for copying is delivered to the outside. Since the copy controlinformation “copy one generation” remains intact in the signalreproduced and delivered to the outside, recording is permissible forthe external device. During recording, however, the copy controlinformation is rewritten to “no more copies” and as a result, any morecopying is prevented. In case a playback stop is carried out or a pauseis taken after start of the playback, if the copy permission period hasalready expired at the time that the playback resumes, the copy controlinformation can be changed to, for example, “no more copy” so as toinhibit copying. As far as one copy operation is concerned, the playbackmay proceed to the end with the copy control information kept to be“copy one generation” and copying may be permitted.

More particularly, a copy longevity period after recording subject tothe copy permission period 306B is controlled. After the copy permissionperiod has expired, another recording apparatus is allowed to moveinformation to another medium on the premise that the originalinformation is erased. If expiration of the copy permission period isdetected through the aforementioned method at the start of playback,information having its copy control information rewritten to “no morecopies” is added with information of move permission period 307B asnecessary and then moved to the external recording apparatus. Theoriginal information is erased from the medium through a method to bedescribed later. Thereafter, if the difference between the recordingtime 305 and the present time indicated by the clock 107 is within themove permission period 307B, move between the media is permissible. Whenthe move permission period expires, it is impossible to perform move anymore. In the absence of the move permission period 307B, the period formove is unlimited. In other words, the move permission period after thecopy permission period has stopped or expired is controlled by the movepermission period 307B.

As set forth so far, in copying information to the external recordingapparatus within the copy permission period, the copy controlinformation on the original recording medium is changed from “copy onegeneration” to “no more copies” as the copying operation proceeds. But,the copy control information can be changed at the end of the copypermission period to permit preparation of a plurality of sheets of copyof one generation.

There are some methods of managing the permission/inhibition of deliveryof the information to be reproduced (playback, copy or move) in a unitof time. The managing method entangles the method of recording theaforementioned control signal. If the retention period and the playbackpermission period or copy permission period are managed every image,that is, every frame, the most stringent management can be carried out.The management per frame, however, imposes a large load on operation ofhardware, involving a problem of erase to be described later.Accordingly, by managing the control signal in a unit of certain time,the load imposed on processing can be alleviated. For example, atolerance of one minute is set up for control of the retention period306A or playback permission period 307A. Then, for a retention period306A of 120 minutes or a playback permission period 307A of 120 minutes,control is allowed to be done between 120 minutes and 121 minutes andthe management can be performed every minute. The tolerance may be setup in a unit of predetermined number of images or in a unit ofpredetermined amount of data.

The move count and the playback count indicated in connection with FIG.9 can be managed as will be described below.

In the case of move, the count is decremented by one in essential eachtime that the move operation is carried out once and a reproductionsignal is sent to the external recording apparatus. If, while the numberis prescribed, the copy control information signal designates “no morecopies”, the copy control information can be changed to “copy onegeneration” and delivered and when recording is carried out with theexternal recording apparatus, the copy control information can bechanged to “no more copies”. Further, only when the external recordingapparatus is adapted to move from the standpoint of erase operation tobe described later, the count can be decremented by one and thendelivered. Contrarily, in the case of the apparatus unadapted to move,the count can be rewritten to 0 and then the control signal can bedelivered, thus disabling any more move. Obviously, the apparatus on thereproduction signal transmitting side must have the erase functionconforming to move as will be described later. A control signalindicative of the erase function may be transmitted to the externalrecording apparatus.

On the other hand, in the case of the playback count, the manner ofmanagement of the playback count matters in the event that, for example,an interruption occurs on the way of playback. A method is availableaccording to which the management is carried out in a unit of contentsand after playback has proceeded for a constant time, the count isdecremented by one. Alternatively, at the time that a stop, putting apause aside, is applied, the count may be decremented by one. Further,at the time that backward feed of the medium, putting a stop aside, isapplied, the count may be decremented by one.

A description concerning the playback longevity period 317 will begiven. When, during playback operation, the playback permission periodstops or ends before the program comes to an end, the reproductionoutput operation can be inhibited but otherwise, delivery of thereproduction output can continue to the end unless the playbackoperation is stopped. In the latter case, one playback operation can becarried out unless the playback longevity period has already expired atthe time that the playback starts. Information for the above purposescan be detected during playback by means of the information detectioncircuit 111 of FIG. 6. The information can be rewritten by means of, forexample, the signal output circuit 106 of FIG. 6. This can furtherpromote the working condition management.

Next, a method of erasing the information on the medium will bedescribed. The term “erase” referred to herein not only signifies eraseliterally but also involves the case of rewriting at least part of theinformation on the medium to disable the effective information to bereproduced. Only the aforementioned effective period management in thereproducing circuit is sometimes insufficient to be versatile in thefuture. If the medium recorded with the information remains, then thereproducing playback will be impossible at present but there is a fearof the future advent of a method that overcomes the present-daypreventive method to make playback possible. From the above point ofview, the information on the medium is erased after playback or at thetermination of the retention period 306A and playback permission period307A, thus further promoting safety. In addition, when theaforementioned move mode is carried out, the information on the mediummust be erased after copying.

Firstly, a unit of information to be erased is considered. It is firstconceivable that when the period runs out, an erase operation is carriedout in a unit of frame. It is also conceivable that the information ismanaged in a unit of larger time. For example, the management at therate of one minute is carried out and information confined within oneminute until the expiration is erased collectively. Alternatively, themanagement is carried out in a unit of plural image frames andinformation confined within a prescribed time until the expiration maybe erased collectively. A similar operation may be undertaken at therate of predetermined amount of data.

Timing of erase will be considered. As described above, the method isavailable according to which the erase timing linking to the retentionperiod and playback permission period in some ways is determined. Inaddition to this, it is conceivable that when information once subjectedto playback is not permitted for repetitive playback, the information iserased at a timing of playback even if the playback timing far precedesthe effective period. In the event that the medium is removed form theapparatus at the expiration of the period and erase cannot be fulfilled,erase operation may be carried out when the medium is mountedsubsequently.

In the case of move, too, it is conceivable that information moved tothe next medium is erased in a unit of frame. Alternatively, theinformation may be managed in a unit of larger time. For example, whenthe information is managed every minute, information confined within oneminute after move may be erased collectively. In an alternative, theinformation may be managed in a unit of plural image frames andinformation confined within a prescribed time may be erasedcollectively. A similar operation may be performed at the rate ofpredetermined amount of data. Further, after one program has completedcopying to the next medium, the whole of the program may be erasedcollectively.

Next, practical erase operation will be described with reference to thedrawings. Erase is made in different ways depending on the type of themedium. An example applied to a disc medium will first be described withreference to FIG. 14.

FIG. 14 is a block diagram showing another embodiment of the informationreproducing apparatus according to the invention. In the presentembodiment, the block diagram of the reproducing circuit shown in FIG. 6is unified with the block diagram of the circuit shown in FIG. 4,additionally having a media type detection circuit 207. Obviously, thereproducing circuit construction as shown in FIG. 7 or 12 can be used inplace of the FIG. 6 reproducing circuit.

FIG. 14 is adapted to a disc medium. The disc medium is sorted into anRW (or RAM) type capable of rewriting records many times and an R typeincapable of rewriting information once recorded. The term“un-rewritable” means “un-erasable” and if erase is to be applied ormove is to be carried out after the expiration of the presupposedeffective period, recording onto the R type disc medium must be rejectedinitially. The media type detection circuit 207 is provided for thispurpose. Thus, on the premise that the R type disc is carried and eraseis made or move is carried out after the expiration of the effectiveperiod, a control signal is sent to the recording signal processingcircuit 203 to prevent delivery of a code to be recorded. For detectionof the medium, some methods have been known which are directed toreading a sign applied outside a recording area of the medium, reading acode precedently recorded at part of the recording area and making adecision on the basis of reflection factor, respectively.

The output of the output control circuit 112 on the reproducing side isalso fed to the recording signal processing circuit 203. On the basis ofthe previously-described retention period and playback permission periodor at the time that move proceeds, the output control circuit 112generates a control signal for commanding an erase operation. Responsiveto this control signal, the recording signal processing circuit 203generates a code for performing erase at a location of interest on themedium. This code can be a code that is meaningless as information. Asdescribed previously, the method is available which manages data in aunit of frame and erases the whole of data. This method is, however,sometimes unpractical from the viewpoint of the time for processing.Even in the case of the management in a unit of frame, the object can beattained sufficiently by erasing only the control signal part as shownin FIG. 8 for instance or especially erasing only the encryptioninformation 309 in the control signal part.

This holds true for the management in a unit of other than the frame,for example, for the management in a unit of time, in a unit of group ofimages or in a unit of prescribed amount of data. For example, when theinformation is managed in a unit of minute, data confined within oneminute until the expiration of the effective period or a control signalof data within one minute after move can be erased. In case encryptedinformation is recorded, a method is available which erases onlyscramble information.

Further, in case the control signal in the unit to be managed is, forexample, encrypted, the scramble information is recorded collectively ata single location on the medium. This information is reproducedcollectively during reproduction inclusive of move, stored at aspecified location in the memory circuit 104 and erased from the medium.If the reproduction is stopped on the way, an operation for recordingagain a control signal for a portion not played back onto the medium iscarried out to simplify the erase process. In this case, for the sake ofpreventing the control signal from being collapsed owing to powerfailure on the way, the whole or at least part of the area for storageof the information in the memory circuit 104 may preferably beimplemented with a non-volatile memory circuit such as a flash memory.Especially, in the case of move, the whole of the program may be erasedcollectively through the method as above after the move operation hasstopped.

Obviously, a unit dedicated to reproduction such as a CD-ROM drive doesnot have the recording circuit block corresponding to the lower half inFIG. 14 but if having a component corresponding to the recording signalprocessing circuit 203 having the function of generating the code forerase, it can operate similarly in terms of circuitry. An apparatususing a hard disc as recording medium can of course dispense with theaforementioned media type detection circuit 207.

Next, FIG. 15 is a block diagram showing another embodiment of theinformation reproducing apparatus according to the invention. In thepresent embodiment, an erasing device 115 is added to the block diagramof the reproducing circuit shown in FIG. 6. The reproducing circuitconstruction in FIG. 7 or 12 can of course substitute for the circuitshown in FIG. 6. The FIG. 15 embodiment is suitable for the tape medium.When the retention period and playback permission period are ruled and aportion once played back cannot be fed backward or when move is carriedout, information on the tape medium is to be erased during reproduction.The erasing device 115 is for this purpose and practically implementedwith an erase head. During reproduction, the output control circuit 112sends a control signal to the erasing device 115 to decide whether anerase operation is performed. For example, when the retention period andplayback permission period are prescribed, an erase operation issometimes carried out following reproduction. As the erasing device 115,a full erase head fixed to a tape running mechanism, a flying erase headcarried on the rotary drum also carrying the video head or another videohead not used as reproducing head in the playback mode as described inJP-A-7-244924.

If the full erase head is used, it must be mounted to a position forerase after scanning of the video head in contrast to the normalposition. If the flying erase head or an unused video head is used asthe erasing device, it must also be mounted to a position succeeding thereproducing head in the course of tape scanning. In the latter case, ifthe mount position satisfies the above condition accidentally but if notso, the height must be changed. Even in the former case, it is necessaryto change the height or to mount another head.

In any methods, the information to be recorded is digital informationand differing from analog information, any problem in quality does notarise when erase is carried out using a DC magnetic field without usingan AC magnetic field. Practically, when erase is carried out whileperforming reproduction, interference due to magnetic induction from theerase head to the reproducing head is difficult to prevent. But thisproblem can be solved using DC. Conceivably, the erasing device can beconstructed of a permanent magnet. But, a mechanism is needed whichmoves the location when the erase operation is not done and besidestension applied to the tape changes depending on whether or not erase iscarried out, thereby raising a problem that the mechanism is difficultto control. In such an event, the aforementioned head may preferably beused as an electromagnet.

As described above, according to the invention, the information to whicha stringent copy limit is set can be recorded temporarily by prescribingthe retention period and playback permission period. Further, since theplayback period is limited, the copyright holders can protect theirright. In other words, compatibility between profits of the user and thecopyright holder can be met. Further, by erasing the information whenthe period expires, security against unauthorized copying can be assuredto advantage. In addition, the information can be erased collectively ina unit of time or data amount or only specified part of the recordinginformation can be erased to simplify the erase process to advantage.

Furthermore, even the information subject to copy limitation of “copyone generation” can be limited temporally by prescribing the copypermission period and therefore, uneasiness of the copyright holderscaused by keeping “copy one generation” intact for a long time can beeliminated. Even when the control information changes to “no morecopies”, by introducing the move mode on the premise that theinformation on the original medium is erased, the user can convenientlyexchange the medium even under the condition that the medium used forcopying is only one. As necessary, the move permission period canadvantageously be limited.

Furthermore, by erasing the information collectively in a unit of timeor amount of data or erasing specified part of the recordinginformation, the erase process can advantageously be simplified. Inaddition, by limiting the move count, playback count and playbacklongevity period, the management of working conditions can further bepromoted.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description and range ofequivalency of the claims are therefore intended to be embraced therein.

1. A reproducing system, comprising: a receiver configured to receive anaudio/video information encrypted according to a predeterminedencryption method and control information related to the audio/videoinformation, the control information for controlling reproduction of theaudio/video information after distribution and at a location differentfrom a distribution location; a memory configured to at leasttemporarily store at least a portion of the audio/video information andat least a portion of the control information; a detector configured todetect at least a portion of the control information, including dataindicative of a first period for enabling a reproduction of theaudio/video information and disabling reproduction after expiration of aprescribed time and a second period, that begins at a start of aninitial reproduction of the audio/video information within the firstperiod and is shorter than the first period, for enabling a reproductionof the audio/video information and disabling reproduction afterexpiration of a prescribed time following the start of the initialreproduction of the audio/video information; a decryptor configured todecrypt the audio/video information encrypted according to thepredetermined encryption method; a reproducer configured to reproduce atleast a portion of the audio/video information from the memoryconsistent with restrictions associated with the first period and thesecond period through decryption by the decryptor; and a controllerconfigured to control at least the reproducer, wherein, in a case wherethe controller confirms that an elapsed time from a start of the firstperiod is within the first period and an elapsed time from a start of aninitial reproduction of the audio/video information is within the secondperiod, the controller is configured to, based on at least a portion ofthe control information detected by the detector, allow the reproducerto reproduce the audio/video information, wherein, in a case where thecontroller confirms that an elapsed time from a start of the firstperiod is out of the first period even if the controller is configuredto control the reproducer to execute a start of an initial reproductionof the audio/video information at a timing when a remaining time of thefirst period is less than the second period and an elapsed time from thestart of the initial reproduction of the audio/video information iswithin the second period, the controller is configured to, based on atleast a portion of the control information detected by the detector, notallow the reproducer to reproduce the audio/video information.